LB7 MBRP 4" Downpipe-Back Aluminum Exhaust

The 4" Aluminum Downpipe Back Exhaust is the bang-for-your-buck on the market for the Duramax LB7. Coming in at just $399.99 it is an extremely affordable exhaust that offers significant power gains and big EGT improvements. This exhaust system is made of high quality aluminized steel and connects directly to the factory or aftermarket downpipes. It does not include a muffler which helps further reduce backpressure and EGTs.

Overall, this is our top recommendation when it comes to LB7 exhaust systems. The lack of a muffler maximizes performance, the aluminum material will help prevent drone, and the price is the best on the market. If you're considering a 5" exhaust, we typically only recommend it for trucks running an upgraded turbo. Going bigger won't hurt - it's just not necessary or worth the extra $ if you don't need it. Furthermore, the aluminum material is slightly less durable than the T409 exhaust systems but the stainless steel is known to produce a lot of drone on the LB7 so aluminum is preferred.

This exhaust system does not include a downpipe - we highly recommend adding a 3" PPE downpipe with this exhaust system to maximize performance.

LB7 4" Exhaust Benefits

• -20-30whp gains and 40-60wtq gains when combined with a tuner & downpipe
• -150-200+ degree drop in EGTs
• -Decreased exhaust backpressure resulting in greater turbo efficiency
• -Improved reliability from lower engine temps and EGTs
• -Better sounding exhaust note

Downpipe Upgrades

This is a downpipe-back exhaust system meaning it does not include a downpipe. The factory downpipe on the LB7 is highly restrictive and one of the most crucial components to upgrade on the LB7. Without a downpipe you likely will not see the performance gains or EGT reductions we mentioned above. Running a larger exhaust but keeping the small, crushed factory downpipe won't result in the same levels of backpressure reduction, meaning less power gains and less EGT reduction.

We highly recommend the 3" PPE Downpipe Upgrade which is a direct bolt-on to this 4" MBRP exhaust.